Effects of ACL graft placement on in vivo knee function and cartilage thickness distributions

Abstract

Injuries to the anterior cruciate ligament (ACL) frequently lead to early-onset osteoarthritis. Despite advancement in surgical techniques, ACL reconstruction has a limited ability to prevent these degenerative changes. While previous studies have investigated knee function after ACL reconstruction, in vivo investigations of the effects of graft placement on in vivo joint function and cartilage health are limited. This review presents a series of studies that used novel imaging and 3D modeling techniques to determine the in vivo placement of the ACL graft on the femur using two different ACL reconstruction techniques. These techniques resulted in two distinct graft placement groups: one where the ACL was placed anatomically near the center of the native ACL footprint and another where the graft was placed anteroproximally on the femur, centered outside the ACL footprint. We quantified the effects of graft placement on graft deformation during in vivo loading and how these variables affected knee motion. Finally, we quantified whether femoral placement of the graft affected cartilage thickness. Our results demonstrate that achieving anatomic graft placement on the femur is critical to restoring native ACL function and normal knee kinematics. Knees with grafts that more closely restored normal ACL function, and thus knee motion, experienced less focal cartilage thinning than did those that experienced abnormal knee motion. These results suggest that achieving anatomic graft placement is a critical factor in restoring normal knee motion and potentially slowing the development of degenerative changes after ACL reconstruction.

A New Stress Test for Knee Joint Cartilage

“…1), indicating that site-specific measurements are needed to accurately capture cartilage response across the tissue. As OA may incur focal tissue changes or defects, such as increased thinning in cartilage sub-regions compared to the overall compartment 30 , the ability to capture focal cartilage changes in a site-specific manner may shed further light into OA etiology 31,32 .…”

Impact of broad regulatory regions on Gdf5 expression and function in knee development and susceptibility to osteoarthritis

“…30 A smaller tibial spine compromises knee stability resulting in increased knee axial rotation and medial-lateral translation, 20 both of which increase shear loads across the medial compartment. 31 Increased cartilage pressure and shear loads in the medial compartment, the most common site of knee OA, result in excessive cartilage wear and tear and are strongly linked to OA development and progression. 32 A shallow trochlear groove results in less congruent patella-femur articulation, with smaller contact area and increased local pressure on the articular cartilage.…”

A comparison of patellofemoral cartilage morphology and deformation in anterior cruciate ligament deficient versus uninjured knees

“…For instance, Frobell et al demonstrated decreased cartilage volume in the femoral trochlea at one and two years post-injury (Frobell, 2011; Frobell et al, 2009). Cartilage thinning has also been observed in ACL reconstructed knees with non-anatomic graft placement (DeFrate, 2017; Okafor et al, 2014). Similar to our findings, Potter et al showed that the risk of patellar cartilage loss triples between years one and two post-ACL injury (Potter et al, 2012).…”